Relay automatic telephone system



March 20, 1951 055 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM Filed July 1, 1948 18 Sheets-Sheet 1 I14 I INVENTOR.

JOHN H. VOSS ATTORNEY March 20, 1951 Filed July 1, 1948 J. H. voss 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM 18 Sheets-Sheet 3 CODE I0 CODES INVENTOR. JOHN H. VOSS ATTORNEY March 20, 1951 J. H. voss 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM ATTORNEY March 20, 1951 .1. Hfvoss 2,546,080

- RELAY AUTOMATIC TELEPHONE SYSTEM Filed July 1, 1948 18 Sheets-Sheet 5 FIG. 5 5705 TRK. IIB

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395 JOHN H. voss ATTORNEY March 20, 1951 "H voss 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM Filed July 1, 1948 18 Sheets-Shet s VFIG.6

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INVENTOR. JOHN H. VOSS ATTOR NEY March 20, 1951 J. H. voss 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM Filed July 1, 1948 18 Sheets-Sheet 7 F l G .7

. TRUNK O ACCESS 3o RELAYS TIO TIOZO JNVENTOR. JOHN H. VOSS ATTORNEY March 20, 1951 J. H. voss RELAY AUTOMATIC TELEPHONE SYSTEM 18 Sheets-Sheet 11 Filed July 1, 1948 I74 Bus use o|2 3 mm m mm l\ 3 Gm m n 7 5 8 b I ll T 0 M s E I N/ 06 T5 v|l|| J v 1 m E m NB .U m m A u. m m

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nss i III6 s s o v ATTORNEY March 20, 1951 J. H. voss RELAY AUTOMATIC TELEPHONE SYSTEM 18 Sheets-Sheet 12 Filed July 1, 1948 INVENTOR. I hU-IN H VOSS ZMKZ ATTORNEY March 20, 1951 Filed July 1, 1948 FIG.I9

J. H. voss 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM 18 Sheets-Sheet 15 FIGZO I O 9 I5 08 29g INVEN TOR.

JOHN H. V0 SS ATTORN EY March 20, 1951 J 5 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM Filed July 1, 1948 18 Sheets-Sheet 14 I29 GSIO I297 I299 JNVENTOR.

JOHN H. voss ATTO RN EY March 20, 1951 Filed July 1, 1948 J. H. voss 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM 18 Sheets-Sheet l5 INVENTOR. JOHN H. VOSS ATTORNEY March 20, 1951 055 2,546,080

RELAY AUTOMATIC TELEPHONE SYSTEM JOHN H. VOSS ATTORNEY xmh E0 2200 4mm OP 18 Sheets-Sheet 1'7 J. H. VOSS RELAY AUTOMATIC TELEPHONE SYSTEM March 20,

Filed July 1, 1948 INVENTOR. JOH N H. VOSS ATTORNEY March 20, 1951 J. H. voss RELAY AUTOMATIC TELEPHONE SYSTEM 18 Sheets-Sheet 18 Filed July 1, 1948 0mm. ownmmt IN V-EN TOR. J OH N H. VOSS OmE fmmQ NNE fillllllllllnlll P .2:

ommz ATTORNEY Patented Mar. 20, 1951 RELAY AUTOMATIC TELEPHONE SYSTEM John H. Voss, Rochester, N. Y., assignor to Automatic Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application July 1, 1948, Serial No. 36,312

Claims.

This invention relates in general to automatic telephone systems and particularly to automatic systems of the all-relay type generally similar to those disclosed in Patent 2,491,291 issued to J. H. Voss et al. on December 13, 1949, and in my copending joint application Serial No. 720,756, filed January 8, 1946, now Patent No. 2,535,764 issued December 26, 1950, and is directed especially to improvements in the handling of large trunk groups, along the lines previously disclosed in my co-pending application Serial No. 790,728 filed December 10, 1947.

In the foregoing patent and applications various arrangements were disclosed for directing calls to preselected idle trunks in trunk groups of ten trunks or less, by means of trunk selecting relays external to the selectors or connectors employed, the units relays in these switches being controlled from the trunk selecting relays on a call to one of said trunk groups. In the foregoing last named application, a method was disclosed for putting a large group of trunks having a common single-digit call number, on two or more tens relays, and then controlling these relays, as well as the units relays, from the associated group of trunk select relays, on all calls to such trunk group.

The main object of the present invention is to provide greater flexibility and economy for the trunk selecting arrangement utilized in connection with the last named co-pending application S. N. 790,728.

The main feature of the present invention is accordingly the connection of the excess trunks from several large trunk groups to a single tens relay, and the operation of this relay, when required, from any of the various groups of trunk select relays associated with these trunk groups. In the stated prior application, the different pairs or sets of tens relays involved, were separately controlled from separate groups of trunk select relays. This prevented the full utilization of the contacts, except where round numbers of trunks, such as twenty or thirty, were involved. The arrangement of the present invention is much more suitable where trunk groups of intermediate sizes are employed, and permits a better use of tens relays, especially'in a selector, where spare contacts cannot be used for subscribers lines, as they can in a connector system.

.Another feature of the invention consists in improvements in the switch circuits for handling ground return lines.

Other objects and features of the invention will be apparent. from the description and claims which follow, when considered in conjunction with the appended drawings, comprising Figures 1 to 18 inclusive, which, when arranged side by side in the manner indicated in Figures 19 and 20, show the invention applied to both a connector and a selector system. In each case only enough equipment is illustrated to enable the operation to be described and understood.

Thus Figures 1 to 6 inclusive, show a IOU-line, all-relay, code-ringing connector, of a type suitable for use with both ground-return and allmetallic lines, including 20-station party lines, in a small 100-line community exchange, but with certain non-essential timing and restrictive features omitted, in order to simplify the drawings, while Figures 7 to 10 show the trunk selecting equipment required for handling two 15-trunk trunk groups connected to the contacts of three of the tens relays of this connector, in the manner indicated in Figures 5 and 6.

Likewise Figures 11 to 14 show a similarly simplified all-relay selector, suitable for use in larger systems, while Figures 15 to 18 show trunk selecting equipment for handling two 15-trunk trunk groups associated with three of? the tens or group relays of this selector, in the manner indicated in Figures 13 and 14.

It should be understood of course, that many other arrangements of large trunk groups are possible with this system, both as to the number of trunk groups, the number of trunksin each trunk group, and the number of tens relays involved. Thus in the present instance, two groups of 11 and 19 trunks respectively, or 14 and 16 trunks or the like'could have been used, instead of two groups of 15. It is also possible to control an almost limitless number of tens relays with only ten single-digit call numbers. In a selector for example, if it should be desired to have only large trunk groups, 10 trunk groups of 11 trunks each could be placed on 11 tens relays, 10 groups of 12 trunks each on 12 tens relays, 10 groups of 13 trunks each on 13 tens relays, etc. Groups of more than20 trunks can also be accommodated just as readily, in many and various combinations, both symmetrical and unsymmetrical;

With further reference tothe drawings, Figure 1 shows the incoming end of the 100 line connector, which may be assumed to be connected to an all-relay linefinder such as shown for example, in the previously mentioned application Serial No. 720,756. The conductors I09 and 191 on the left of this figure are the talking con- Figure 2 shows eight additional control relays for this connector, numbered 2 I9: to 2% inclusive;-

Relay 2| El is a back-bridge relay, 223 is a ringing-digit transfer relay, 238 is a drainf relay,

240 is a ringing pick-up relay, 25El isa '-r'ing cut-off relay, 268 is a ring reversing relay,

and relays 27B and 28Il are ringing relays,'the

first of which rings to the negative side of a called line, and the second to the positive side.

Figure 3 shows nine more miscellaneous control relaysi for this connector, numbered '3 I to 38Il,.of-twhich:-:relay :3 I e is a busy relay, 329 isla switching? relay,:.35fi and \335are fcode group selecting2re1ays,' 3&5; 353 and 359' are digittrans-* fer. relays, and .310 and-x380 are dialling transfer)?- relay's;

Figure 4 shows the-connector digit register con sisting of ten countingfrelayswnumbered Mil toi lllti inclusivearranged in a well known form ofcounting chain,: with'threefcounting control" relays on thele'ftznumbered. ii 29. and- .39 for. extending the local-'spulsing circuit to thei'difiei'ent counting-relaysin'"turn as-required; on th'e'left 1 sideofithisflgure: a ringing interrupterpthe dee tailsiof the" construction of which are: immaterial:

from the: viewpoint 1 of the. invention, is indicated byethet rectangle 28.3v

Figure-5 shows three-of the "tens Lrelays employed' in .this connector; numbered550, 560 and 510, while Figure 6 shows: another Ltens relay numbered fi lflgtwo'units relays numbered 620 and 630, and a units'switchin'gtrelay 'SIIL' In practice; *five 'units" relays are employed; each con-.

trolling two'sets oflinecontactseach comprising two pairiof line-conductorcontactsand one pair of'test conductor 'contactsz- Each tensi relay is similarly provided with ten sets "of-line contacts, although -onlyxfour sets, comprising the 1st, 5th,

6th and 10th are shown on each relay in the drawings. It may also be'noted that three trunk groups A, B1? and-C are connected tothe linecontacts of the four; tens relays "shown. Trunk group 1A isa 15 'trunkgroup, of which the. first ten trunks. are connected to tens relay 64H and'the last five'to the" 6thito 10th contact" sets of1tens relay 559;: trunk. group Bf'i also a l5'ltrun'k' group,-of which the first ten trunks are i connected to tens relay 56B and the last five to' contact sets'l to 5 ofrelay 5541;- and trunk group C 'is'a simple group of five trunks all connected to contactsontens "relay 5H3, merely to show hdw small trunk groups may be mixed with large groups'in the-same switch. The remaining contacts of relay" 519 are assumed to be connected to subscribers lines. H

Figure-7 shows a group of trunk access relays,

whichform a part'of the trunk selecting equipment.v each group.v 0fiC01'1I1e'Ct0IS, WiGh an access relay such as III or 139"ther.ein'for each switch in the associatedconnector-group:- Thus, in Figure' 7, relay H0 is associated with-the connector switch of Figures 1 to 6, while relay 13D isassociated with th'elasts switch in thesame group,1 indicated by' Relay I56 is a lockout'relay i the-rectangle -12 5.

One such-group is ordinarilyrequired for a which operates when any access relay is operated, and momentarily prevents the operation of any other access relay in the same group. Relay I60 is a normally operated slow to release kick-off relay which releases if a trunk call fails to switch through promptly, to busy the connector and cause the trunk selecting relays to advance to a new trunk.

In the upper part/of Figure 8 is shown a group of trunk group relays associated with the trunk select relays for the first 15-trunk group, which are shown in Figures 9 and 10. In the lower part of Figure 8, the rectangle 825 represents a similar unit of-trunkigroupirelays associated with the trunkselectrelays'serving the second 15-trunk thesame manneri asrelayrfifim In caseswhere there is onlygrouprelay involved, relay 850 may be omitted; and negative battery connected direct to the back contact ofmake-before-break springs BI I.

Figures and. 10, asindicatedin the preceding paragraph, show the.trunk:.select:relays for. the first 15-min group Af.

relay such as 828-01 IIIZG isprovided for each trunk in the group. These busy relays are nor' mally operated-through contacts in the associated trunk repeaters, not shown, and release when the corresponding trunk is seized Icy-a call. The pre-. selectrelays operate one at a timerin rotation, as-the trunks are taken into use, to preselect the next idle trunk; Relay Ifl-is a'reset relay which operates momentarily-when the-last trunk isseized-by a 031118.116. relay-I095 is an alltrunks-busy relay. Only a portion of the trunk busy-and preselect relays are shown", inorderto conserve space.

With reference to the selector system, Figure 11 shows the incoming ,endof'one of the selectors, which may also be assumed to be connected to an associated all-relay lineflnder such as illustrated in the previously :mentionedrapplication Serial No. 720,756 via the line, test, hold and link busy conductors IIIlll' to H05 shownzon the left of the'sheet. This figure also includes five control'relays, numbered II I0 to I I5l3,"of which II II is the switch through relay, II2II the line relay, Il3il'the release relay, H40 the dialling transfer relay, and IIEG theWbusy relay, in addition to a units switching relay II'III.

Figure 12 shows'the selectordigit register'comprising te counting relays numbered I2I6 to' I266, and three counting control relays'nunn. bered eihiil and GIJQ These relays aresimilar to those of the connector digitiregister. of Figure 4 and operate similarly. The functions .are slightly difierent however, due to the difference in the functions of the two switches:

Figure 13 shows three of the tens relays used with'this'selector, numbered I340, I356 and I358, while Figure 14 shows anotherxtens relay numbered I430, and two ofhthe fiveunits relays required, numbered' I4III andvI42iL. Threetrunk Relay 850, also,

In thisunit, a trunk busy relay suchaas'illfl. or IllI'iLand a preselect. 

